1900: A physics genius wandering around Europe

Chapter 661: Paper Published! Shocking the Academic World! The Neutron Race! A Storm is Brewing! At

Chapter 661: Paper Published! Shocking the Academic World! The Neutron Race! A Storm is Brewing! At the End of the Bombardment, I Make My Move!
After Fermi obtained artificial radioactivity by bombarding lithium with neutrons, he was not satisfied with that.

He wanted to further understand the mechanism of the entire nuclear reaction.

With the discovery of positrons and Ligvii's theory of nuclear reaction analysis, physicists are now beginning to try to explain the mechanisms of artificial nuclear reactions.

For example, Elena and her husband recently published a paper that explains in detail the mechanism of their first discovery of artificial radioactivity.

Irene's experiment involved bombarding aluminum with alpha particles, producing radioactivity, and the radiation consisted of antielectrons.

After detailed and precise research, this process can be written as a nuclear reaction equation:
①：He(2，4)+Al(13，27)→P(15，30)+n(0，1)；

②：P(15，30)→Si(14，30)+e(1，0)。

In this context, the first number in parentheses represents the number of protons; the second number represents the sum of the number of protons and neutrons.

The alpha particle, namely helium (He4), has two protons and two neutrons, so it is (2, 4).

The positron e carries a unit positive charge, so it is equivalent to a proton, hence its coordinates are (1, 0). (The notation is the same, but the underlying structure is different.)
n represents a neutron, so the number of protons is 0.

The above equation can be explained in words as follows:
When a helium (He4) nucleus collides with an aluminum (Al27) nucleus, a phosphorus (P30) nucleus is first generated.

Phosphorus P30 is a radioactive isotope of phosphorus, so it is radioactive immediately after it is formed. After emitting a counter-electron, it forms silicon Si30.

This is the principle behind Elena's initial discovery of artificial radioactivity.

Once the concept of nuclear reaction is grasped, everything becomes clear and simple, much like balancing a chemical equation.

However, in this era, the difficulty is still very high.

Here, some people may raise questions.

"Wait a minute, author, I'm a little confused."

"I see on the periodic table that phosphorus (P) has 15 protons and a relative atomic mass of 30.97."

"But the mass of an atom is determined by protons and neutrons, while the mass of an electron is thousands of times smaller and negligible."

"Then why isn't the relative atomic mass of phosphorus (P) an integer?"

Congratulations, you've discovered a very interesting question.

This is why the atomic nucleus must include the number of protons and neutrons in the nuclear reaction equation.

Take phosphorus (P) as an example.

Currently, 23 isotopes of element P have been discovered.

So how do we distinguish these isotopes in daily communication and research?
The answer is the proton number plus neutron number representation.

We already know that the number of protons in each element is fixed, because the number of protons represents the element's position on the periodic table.

The element P has 15 protons, meaning that its atomic nucleus contains 15 protons.

The lowest mass isotope of phosphorus contains only 9 neutrons in its nucleus.

Therefore, this isotope can be written as [P24].

Similarly, the 23 isotopes of element P are P24 to P46.

Of these isotopes, only P31 is the most stable and non-radioactive, while all the other isotopes are radioactive.

Therefore, the P30 mentioned above also contains radioactive isotopes.

When we say P30, we are not actually referring to the element phosphorus, but rather to the isotope of phosphorus that has 15 neutrons.

You should understand the difference now.

Phosphorus, phosphorus isotopes, phosphorus atoms, and phosphorus nuclei are all different concepts and should not be confused.

Okay, now let's get back to the main topic.

Why is the relative atomic mass of element P in the periodic table 30.97?

The answer is simple.

We know that the relative atomic mass of P24 is 24, the relative atomic mass of P30 is 30, and so on.

However, in the periodic table, the relative atomic mass Ar refers to the Ar of a particular element, not the Ar of a particular isotope of a particular element.

Since different isotopes are present in different proportions in nature, they need to be summed up and averaged to represent the entire element.

即：(24×1%)+(25×2%)++(31×80%)+(46×1%)=？

Since P31, the most stable isotope, has the highest proportion, the final calculated result is close to 31, which is 30.97.

The above explains the relationship between artificial nuclear reactions, artificial radioactivity, and relative atomic mass.

It can be said that the discovery of artificial radioactivity has greatly enhanced people's in-depth understanding of the periodic table.

Since then, isotope research has had theories and methods, becoming a popular field in physics and giving rise to many useful technologies.

At this moment, after careful research, Fermi finally figured out the artificial radioactivity mechanism of lithium.

The nuclear reaction equation is as follows:

①：Li(3，6)+n(0，1)→Li(3，7)；Li7是锂元素的一种放射性同位素。

②：Li(3，7)→He(2，4)+H(1，3)。放射出α射线（氦原子核）。

He smiled at the group of teenagers and said:
"This research will surely set off a new wave of excitement in the field of nuclear physics!"

Everyone was in high spirits.

Fermi is about to reignite the glory of Italian science.

And they are the Pope's right-hand men.

1926 9 Month 25 Day.

The Fermi team's paper was published on the cover of the journal Nature.

The article shocked the entire physics community as soon as it was published!
At the time when Professor Bruce reignited the theoretical physics craze.

Fermi, located in Italy, the scientific heartland of Europe, has once again unleashed his accumulated expertise, setting a new benchmark for experimental physics.

This is another groundbreaking discovery following antimatter.

The efficiency of using neutrons as a bombardment source to produce artificial radioactivity is simply astonishing!
"Fermi is amazing!"

"He actually thought of using neutrons as the bombardment source."

"This is different from everyone else!"

"And he also found the strongest neutron source."

"As expected, a genius is a genius. Even after transitioning from theory to experiment, he remains a genius."

Fermi's story quickly spread and inspired countless people.

Following this, Italian Education Minister Corbino, at a meeting of the Italian Academy of Sciences, highly praised Fermi's team's achievement.

"Thank you, Fermi and his team, for bringing glory to Italy!"

Fermi humbly stated:

"This is just the first step in our team's achievements."

"Next, we will bombard each element one by one in the order of the periodic table to find more artificial radioactivity."

The audience burst into applause.

Young people are so clever!
Cavendish Laboratory, UK.

Rutherford couldn't help but burst into laughter after seeing the materials Fermi sent him.

Fermi detailed in his materials the method of creating neutron sources using radon gas, which was not elaborated on in his paper.

It can be said that whoever masters this method will gain a huge advantage in the upcoming wave of neutron bombardment.

"Fermi is a very good young man who knows how to be grateful."

The other party reported to Rutherford immediately, which greatly pleased the latter.

However, given Rutherford's current position, he wouldn't stoop to competing with younger people for credit.

So he handed the document to Chadwick and then left it at that.

"Experimental physics is getting more and more fascinating!"

Chadwick was shocked after reading Fermi's data!
Be nice.

He felt as if he were holding stacks of Nature journal articles, not just data.

"If we were to bombard the periodic table with these elements, we'd probably be publishing papers non-stop."

Unfortunately, while these papers would certainly be very attractive to graduate students, they were just so-so for him.

Since missing the neutron, Chadwick has been desperately searching for his next breakthrough discovery.

Without a doubt, Fermi's discovery was absolutely groundbreaking.

But he was the first to try something new, so he gained the most fame.

No matter how many artificial radioactive materials are discovered using neutrons, those who follow are simply accumulating a database.

Therefore, Chadwick didn't want to follow Fermi's path. This kind of work could be left to graduate students; Cavendish had plenty of students anyway.

He has bigger ambitions.

"Perhaps neutrons could be used to bombard other phenomena that are not yet shocking!"

The mystery of the neutron has only just been partially revealed.

France, Radium Institute.

Elena and Jolio were shocked after reading Fermi's paper.

The other party has found a more efficient method for creating artificial radioactivity, which is much better than relying solely on luck.

Elena exclaimed in surprise:

"I never knew neutrons could have such a function?"

"According to Fermi's explanation, neutrons are uncharged, so they can more easily come into contact with the atomic nucleus and cause nuclear reactions."

Joliot also remarked:
"It sounds simple, but it's extremely difficult to actually do."

"Especially the neutron source that Fermi used, I just tried it, and it's not so easy to obtain."

"There must be some unique technique involved."

Unfortunately, this was not clearly stated in his paper.

Jolio thought this was normal.

Every laboratory has its own secret weapon, which is the source of its confidence to stay ahead of others.

This has nothing to do with hindering scientific development.

Moreover, Fermi clearly stated in his paper that the strongest neutron source could be created using radon and beryllium; he couldn't possibly just reveal all the parameters directly.

This is the result of his hard work over the past six months.

If anyone thinks that Fermi deliberately withheld knowledge and hindered scientific progress...

Fermi could easily say: From my perspective, I am clearly advancing science.

Irene can understand.

"Fermi's laboratory has just been established and is not yet very powerful."

"He must have his own ambitions, wanting to find more artificial radioactivity."

"So, if we can get a slight lead, we should."

Jolio nodded.

However, Elena's next sentence exuded domineering power.

"Unfortunately, radiology is the exclusive field of study for our Curie family."

"Nothing can be hidden from me."

"It's just a neutron source. Watch me crack its mysteries in three days!"

"I want to have a scientific research competition with Fermi!"

As the discoverer of artificial radioactivity, Elena was obviously very interested in finding more artificial radioactivity and summarizing the patterns from it.

Wow!
Joliot's eyes sparkled.

Who wouldn't love such a strong female lead?

Kaiser Wilhelm Institute for Chemistry, Germany.

Meitner, Hahn, and Strassmann, a close-knit trio, also showed great interest in Fermi's paper.

For them, neutron bombardment is still uncharted territory, and there may be unexpected surprises.

Hahn said with a smile:

“Meitner, I heard your nephew is at Professor Bohr’s institute.”

"Does he also want to study neutrons?"

Meitner laughed:
"Yes, Frisch also asked me to send him more papers."

"The Bohr Institute has also recently expanded its research areas in experimental physics."

"He took on many tasks."

Strassmann exclaimed:

"Who would have thought that Professor Bohr, who was once famous in the academic world, would have to bow to reality?"

"Theoretical physics is really too difficult."

"I don't understand a thing about Professor Bruce's latest quantum electrodynamics."

Meitner and Hahn burst into laughter.

Strassmann was a chemist, and his physics background was already weak, so getting access to Professor Bruce's paper was an impossible task for him.

Institute of Physics, University of Copenhagen, Denmark.

Bohr sat in his office.

After returning from Asia, he, like Dirac, suddenly had a new idea.

"Could we apply the ideas of quantum field theory to the atomic nucleus?"

Since atomic nuclei can undergo nuclear fission, is it possible to describe the fission process theoretically?

"In other words, I want to create a theoretical model of the atomic nucleus to explain all nuclear phenomena!"

His eyes grew brighter and brighter, as if he had found a path that no one had ever tried before.

It must be said that Bohr had great ambitions, and Dirac's achievements greatly stimulated him!

This peerless genius of the previous generation has also been silent for a long time.

Borneo.

Yu Yin's eyes widened in disbelief.

The principal had just told him that neutrons might hold a great secret, and in the blink of an eye, Fermi used neutrons to bombard artificial radioactivity.

"What a coincidence!"

Yu Yin was extremely excited.

Fortunately, he had already started preparing. If he could overcome the challenge of neutron acceleration, he would definitely have a greater advantage than anyone else.

Moreover, the Institute of Atomic Energy is still the only laboratory with a cyclotron accelerator.

Next, experimental physics will inevitably have the voice of the Institute of Atomic Science.

For a moment, even the usually low-key Yu Yin felt a surge of heroic spirit.

Experimental physics is more intense and exciting than theoretical physics today.

After all, for the latter, there is no difference between being one day earlier or one day later.

If you understand the theory, you understand it; if you don't, you don't. There's no difference between thinking about it today and thinking about it tomorrow.

However, there is a big difference between doing the experiment today and doing it tomorrow.

A famous female protein scientist in later years once said on Weibo that she couldn't sleep all night in order to publish her article ahead of schedule.

Inside the Li family mansion.

Ridgway paid no attention to the shock caused by Fermi.

Now, all his attention is focused on the little baby in his hands.

This was his ninth child, a daughter born to Song Xianglan, named Li Zhenzhen.

Li Qiwei was captivated by the adorable appearance of the glutinous rice cake, which filled him with affection and touched his heart.

After a long while, he reluctantly handed the baby over to the nanny to take away.

Li Qiwei walked to Xianglan's side and said softly:
"You have worked hard."

Xianglan's face was pale, but she still spoke softly:

"Sir, aren't you going to the research institute today?"

Li Qiwei said:
"not going."

"I'll be staying home with you guys for a while now."

Xianglan felt a sweet warmth in her heart and revealed a charming smile.